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ocfs2: Fix max offset calculations

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ocfs2_max_file_offset() was over-estimating the largest file size for
several cases. This wasn't really a problem before, but now that we support
sparse files, it needs to be more accurate.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
This commit is contained in:
Mark Fasheh 2007-07-20 12:56:16 -07:00
parent ce76fd30ce
commit 5a25403175
1 changed files with 39 additions and 27 deletions
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66
fs/ocfs2/super.c
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@ -316,39 +316,51 @@ static void ocfs2_destroy_inode(struct inode *inode)
kmem_cache_free(ocfs2_inode_cachep, OCFS2_I(inode));
}
/* From xfs_super.c:xfs_max_file_offset
* Copyright (c) 2000-2004 Silicon Graphics, Inc.
*/
static unsigned long long ocfs2_max_file_offset(unsigned int blockshift)
static unsigned long long ocfs2_max_file_offset(unsigned int bbits,
unsigned int cbits)
{
unsigned int pagefactor = 1;
unsigned int bitshift = BITS_PER_LONG - 1;
unsigned int bytes = 1 << cbits;
unsigned int trim = bytes;
unsigned int bitshift = 32;
/* Figure out maximum filesize, on Linux this can depend on
* the filesystem blocksize (on 32 bit platforms).
* __block_prepare_write does this in an [unsigned] long...
* page->index << (PAGE_CACHE_SHIFT - bbits)
* So, for page sized blocks (4K on 32 bit platforms),
* this wraps at around 8Tb (hence MAX_LFS_FILESIZE which is
* (((u64)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1)
* but for smaller blocksizes it is less (bbits = log2 bsize).
* Note1: get_block_t takes a long (implicit cast from above)
* Note2: The Large Block Device (LBD and HAVE_SECTOR_T) patch
* can optionally convert the [unsigned] long from above into
* an [unsigned] long long.
/*
* i_size and all block offsets in ocfs2 are always 64 bits
* wide. i_clusters is 32 bits, in cluster-sized units. So on
* 64 bit platforms, cluster size will be the limiting factor.
*/
#if BITS_PER_LONG == 32
# if defined(CONFIG_LBD)
BUILD_BUG_ON(sizeof(sector_t) != 8);
pagefactor = PAGE_CACHE_SIZE;
bitshift = BITS_PER_LONG;
/*
* We might be limited by page cache size.
*/
if (bytes > PAGE_CACHE_SIZE) {
bytes = PAGE_CACHE_SIZE;
trim = 1;
/*
* Shift by 31 here so that we don't get larger than
* MAX_LFS_FILESIZE
*/
bitshift = 31;
}
# else
pagefactor = PAGE_CACHE_SIZE >> (PAGE_CACHE_SHIFT - blockshift);
/*
* We are limited by the size of sector_t. Use block size, as
* that's what we expose to the VFS.
*/
bytes = 1 << bbits;
trim = 1;
bitshift = 31;
# endif
#endif
return (((unsigned long long)pagefactor) << bitshift) - 1;
/*
* Trim by a whole cluster when we can actually approach the
* on-disk limits. Otherwise we can overflow i_clusters when
* an extent start is at the max offset.
*/
return (((unsigned long long)bytes) << bitshift) - trim;
}
static int ocfs2_remount(struct super_block *sb, int *flags, char *data)
@ -1259,8 +1271,8 @@ static int ocfs2_initialize_super(struct super_block *sb,
int sector_size)
{
int status = 0;
int i;
struct ocfs2_dinode *di = NULL;
int i, cbits, bbits;
struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;
struct inode *inode = NULL;
struct buffer_head *bitmap_bh = NULL;
struct ocfs2_journal *journal;
@ -1281,7 +1293,9 @@ static int ocfs2_initialize_super(struct super_block *sb,
sb->s_export_op = &ocfs2_export_ops;
sb->s_flags |= MS_NOATIME;
/* this is needed to support O_LARGEFILE */
sb->s_maxbytes = ocfs2_max_file_offset(sb->s_blocksize_bits);
cbits = le32_to_cpu(di->id2.i_super.s_clustersize_bits);
bbits = le32_to_cpu(di->id2.i_super.s_blocksize_bits);
sb->s_maxbytes = ocfs2_max_file_offset(bbits, cbits);
osb->sb = sb;
/* Save off for ocfs2_rw_direct */
@ -1341,8 +1355,6 @@ static int ocfs2_initialize_super(struct super_block *sb,
goto bail;
}
di = (struct ocfs2_dinode *)bh->b_data;
osb->max_slots = le16_to_cpu(di->id2.i_super.s_max_slots);
if (osb->max_slots > OCFS2_MAX_SLOTS || osb->max_slots == 0) {
mlog(ML_ERROR, "Invalid number of node slots (%u)\n",